This is what RowingCoach looks like during a training. Of course you can mount the iPhone in any orientation: landscape or in portrait.
The history of your workouts is always there, giving you fast access to all the information and even indicating if you recorded a workout with your Apple Watch or with your iPhone.
The information rich activity screen gives you all necessary information at a glance in big enough font size well adapted to active engagement, both on the 42mm and 38mm Apple Watch.
Of course you can also look at your recorded workouts on the Apple Watch. The detailed view gives you all important information and even shows you a map of your training.